Massive and rapid COVID-19 testing is feasible by extraction-free SARS-CoV-2 RT-qPCR

Ioanna Smyrlaki; Martin Ekman; Martin Vondracek; Natali Papanicoloau; Antonio Lentini; Johan Aarum; Shaman Muradrasoli; Jan Albert; Björn Högberg; Björn Reinius

The copyright holder for this preprint (which was not peer-reviewed) is freeze-thawed (x-axis) extracted samples, using the E gene (cross) and RdRP (star) primer-probe sets. ND: not detected. (c) Heatmap of CT from diagnos�cs performed on 85 clinical samples using extracted RNA (E, RdRP) and hid-RT-qPCR (N1, RdRP), ranked by E-gene CT. Control for RNA degrada�on by RT-qPCR for RNase P transcripts in the same samples is show on the right. Two pa�ents, marked with asterisk, nega�ve in extrac�on-based rou�ne diagnos�cs but posi�ve by hid-RT-qPCR were later re-tested and confirmed to be SARS-CoV-2 posi�ve (see Results). The pa�ent marked with a ring was not re-tested. Three samples, marked with hash, were called COVID-19 posi�ve by rou�ne diagnos�cs, but not by any primer-set in hid-RT-qPCR. (d) Boxplots of CT increase when the same nasopharyngeal swab samples were inac�vated at 65°C for 30 min versus 95°C for 15 min. All rights reserved. No reuse allowed without permission. the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.